Humans are perceptive to various types of mechanical vibrations. When the mechanical vibration falls into a specific frequency range, it may be heard as an audible sound. In a variety of applications the acoustical properties of a product may play an important role. A product may be designed to strengthen or attenuate sounds. Examples of such products are insulating or isolating panels, audio systems, loudspeakers or earphones. Acoustical properties of a product may depend at least to some extent of material(s) used in the product.